1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to a therapy device having a deployable treatment needle with a plurality of tines deployable in a straight path from said needle.
Uterine fibroids are benign tumors in the uterine wall and are the most common tumor of the female pelvis. Fibroids afflict up to 30% of women of childbearing age and can cause significant symptoms including discomfort, pelvic pain, mennorhagia (excessive bleeding), anemia, infertility, and miscarriage. While fibroids may be located in the muscle (intramural), adjacent to the endometrium (submucosal), or in the outer layer of the uterus (subserosal), and can grow up to several centimeters in diameter.
Current treatments for fibroids include both pharmaceutical and surgical intervention. Pharmaceutical treatments include the administration of NSAIDS, estrogen-progesterone combinations, and the like. Medications, however, are generally ineffective and are palliative rather than curative. Surgical interventions include myomectomy, where fibroids are removed in an open surgical procedure requiring laparotomy and general anesthesia, and hysterectomy, involving complete surgical removal of the uterus. Both these procedures are long and have significant blood loss.
As improvements over open surgical procedures, several minimally invasive procedures have been developed. Laparoscopic myomectomy is a laparoscopic procedure requiring highly skilled laparoscopic gynecologists. Uterine artery embolization relies on blocking the uterine artery supplying blood to the fibroid by injecting small particles. While sometimes effective, common complications of arterial embolization include infection, premature menopause, and severe pelvic pain. A third approach relies on complete endometrial ablation, which is generally effective for treating bleeding but less reliable for treating fibroids.
More recently, and of particular interest to the present invention, the use of radiofrequency needles and other ablation elements for treating individual fibroids via a transvaginal approach has been proposed. As described, for example, in published U.S. Patent Applications 2006/0189972; 2007/0179380; 2007/0249936; and 2008/0033493, each of which is commonly assigned with the present application, a probe carrying a needle is used to treat individual fibroids. The probe carries on-board ultrasonic or other imaging so that the needle can be guided into the fibroid under direct observation.
While effective in many cases, the use of a single needle for treating fibroids and other solid tissue masses has certain shortcomings. In particular, the volume of tissue that can be treated by a single needle is limited. Even if large diameter needles are used, the surface area of the needle limits the amount of energy that can be imparted into the tissue and ultimately limits the distance from the needle that can be effectively treated.
To increase the effective volume that can be treated using a single needle deployment, the use of multiple, simultaneously deployed needles has been proposed. Of particular pertinence, U.S. Pat. No. 6,050,992 describes a system for deploying multiple everting needles from a single central cannula. In some instances, the needles can be deployed over an outwardly curving surface (see FIG. 9). The needles, however, are generally intended to be pre-shaped so that they evert outwardly, as shown in FIG. 16. U.S. Patent Publication No. 2007/0006215 also describes a needle having multiple stylets which are outwardly deployed over outwardly curving ramps. Because of the limited diameter of the central needle, the ramps must be relatively steep and cover a relatively short distance to gain the desired outward deflection. The use of such short, relatively steep ramps can impart excessive stress to the needles being deployed, particularly if the needles are not pre-shaped in their outwardly curved configuration.
For these reasons, it would be desirable to provide needle structures and deployment assemblies capable of deploying multiple needles, tines, or other components in order to increase the volume of tissue to which radiofrequency or other electrical energy can be delivered. It would be further desirable to provide such multiple needle delivery structures and deployment assemblies where the diameter, width, length, and other dimensions of the structure may be minimized. It would be still further desirable to provide such multiple needle deployment structures and deployment assemblies which have a reduced or minimized insertion force for advancement through solid tissue. It would be additionally desirable to provide a needle delivery structure in which placement of the needle or electrode is predictable. At least some of these objectives will be met by the inventions described hereinbelow.
2. Brief Description of the Background Art
The following US published applications discussed above are relevant to the present invention: 2006/0189972; 2007/0179380; 2007/0249936; and 2008/0033493. The disclosures of each of these applications is incorporated herein by reference. See also U.S. Pat. No. 6,050,992 and US 2007/0006215.